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Cancer Immunotherapy exploiting engineered antibody fragments against prostate-specific membrane antigen
Das, Gargi ; Bařinka, Cyril (advisor) ; Vaněk, Ondřej (referee) ; Ormsby, Tereza (referee)
Prostate cancer (PCa) remains a leading cause of male cancer-related mortality, necessitating thus the development of novel therapeutic approaches as conventional treatments have limited efficacy. Prostate-specific membrane antigen (PSMA) is an established biomarker for both imaging and therapy of PCa, as it is highly upregulated in neoplastic PCa tissues and metastatic castration- resistant prostate cancer. Consequently, immunological targeting of PSMA has gained significant attention as a therapeutic platform for the management of the disease. The thesis is focused on engineering of antibody fragments and fusion proteins derived from the high affinity anti-PSMA 5D3 monoclonal antibody that can be used as immune cell engagers to target and eliminate PSMA-positive cells. To this end, we engineered 5D3 single chain variable fragments (scFv) that were subsequently fused to anti-CD3 scFv and CP33 sequences, creating thus immune cell engagers targeting T-cells (BiTE) and monocytes (5D3-CP33), respectively. The engagers were expressed in insect cells, purified to homogeneity and their biophysical and functional characteristics evaluated using size exclusion chromatography, differential scanning fluorimetry, ELISA and flow cytometry. Ensuing cell-based assays revealed that both BiTE and 5D3-CP33 can...
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Roles of histone H3 lysine methylation in the gene expression regulation
Čizmazia, Viliam ; Veverka, Václav (advisor) ; Ormsby, Tereza (referee)
Viliam Čizmazia Roles of histone H3 lysine methylation in the gene expression regulation Abstract Histone post-translational modifications play a key role in epigenetic regulation of chromatin land- scape and various cellular functions. They can directly mediate interactions between DNA and histones, but also represent recognition signals for specific reader proteins. A particular type of these modifications, lysine methylation, marks a number of specific sites within the terminal as well or globular regions of histone proteins and encodes for various instructions for DNA-related processes such as gene transcription. The profiles of individual lysine methylations are regulated by specific methyltransferases (writers) and antagonizing demethylases (erasers). Their deregula- tion is often associated with diseases such as developmental abnormalities or cancer. For this rea- son, a number of histone-modifying enzymes are considered attractive therapeutic targets. This review is focused on key players and mechanisms underlying the deposition of the most important histone H3 lysine methylations, their genomic distribution and contextual roles in transcriptional events. In addition, it highlights the importance of structure-based approaches in exploring the molecular details behind the activity of histone...
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Biochemical tools for targeting immunomodulatory receptor CD73
Poukarová, Magdalena ; Ormsby, Tereza (advisor) ; Hlouchová, Klára (referee)
New approaches to cancer treatment are investigated because cancer remains one of the most abundant causes of death. One of the promising fields of oncology is immunotherapy, which is based on the activation of immunity to eliminate malignant cells. Several immunotherapy drugs have already been approved and are being used; however, only a part of patients responds with the desired efficiency. In recent years, ecto-5'-nucleotidase CD73 emerged as a potential new target of immunotherapy. The expression of this GPI-anchored enzyme at the extracellular membrane is significantly up-regulated tumour cells and in immune cells of the tumour microenvironment. CD73 catalyses the hydrolysis of AMP to immunosuppressive adenosine, therefore contributing to the immunosuppressive environment in the tumour and participating in resistance to immunotherapy. CD73 appears to be a promising target for a combination treatment to improve the effect of other immunotherapy drugs. So far, several clinical trials of CD73 antibodies and small-molecule inhibitors have been conducted. This diploma thesis describes the development of new biochemical tools for CD73. DNA- linked Inhibitor ANtibody Assay (DIANA), a sensitive method that enables the measurement of the binding affinity of a small-molecule inhibitor to a protein, was...
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MTH1 protein, its role in cancer cells and targeting in anticancer therapy
Poukarová, Magdalena ; Ormsby, Tereza (advisor) ; Doubravská, Lenka (referee)
MTH1 is a protein belonging to the NUDIX hydrolase family. It helps cancer cells to cope with oxidative stress caused by tumor transformation. MTH1 hydrolases oxidized forms of deoxyribonucleotidetriphosphates (dNTPs), thus protects the cell from mutations, helps to maintain genomic integrity and prevents senescence and cell death. Unlike cancer cells, for which MTH1 activity is essential, its expression is very low in healthy cells. Therefore, MTH1 was considered as a potential therapeutic target for the cancer treatment. Several generations of MTH1 inhibitors have been developed. However, the results of testing their anticancer activity were often contradictory. The aim of this work will be to show the function of MTH1 protein, its role in cancer cells and to discuss the path that led to the development of successful inhibitors. Key words: MTH1, cancer, oxidative stress, 8-oxo-dGTP, MTH1 inhibitors
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Studies on immunoreceptor signaling molecules
Ormsby, Tereza ; Hořejší, Václav (advisor) ; Černý, Jan (referee) ; Špíšek, Radek (referee)
A delicate balance in the number, specific type and function of leukocytes is required for proper functionality of the mammalian immune system. Innate immunity, which quickly recognizes pathogens, represents the first line of defense. Later, a more specific response is generated via adaptive immunity. Deregulation of the immune system is manifested by the inability to control infection, development of allergic, autoimmune disorders or even cancer, and ultimately can lead to death. To fulfill their functions, cells develop an intricate network of intra- as well as extra-cellular molecules organized into signaling cascades, which allows them to communicate between each other. Better understanding of the molecular mechanisms of signaling pathways in leukocytes is critical for design of efficient therapies. In this thesis, leukocyte signaling was studied in several aspects. First, the role of adhesion molecules in pathogenesis of cervical cancer and the regulation of their expression was investigated. The second publication describes a new transmembrane adaptor protein (TRAP), called prolin rich 7 (PRR7), as a potentially interesting regulator of signaling and apoptosis in activated T cells. The final publication characterized the role of the Btk kinase downstream of the triggering receptor expressed...
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